Glass is known to be extremely strong in the freshly manufactured stated; for example, by drawing (fusion draw or slot draw), the float process and other methods. However, the strength rapidly deteriorates as the surface becomes flawed. The flaws can be generated when glass contacts other surfaces and becomes scratched, abraded or impacted and chipped. Damaging contact with other surfaces can be avoided if the glass' surfaces, faces and/or edges, are covered with a protective material; for example, adhesive plastic or paper materials, and polymer films. However, these methods are labor intensive, frequently require covering surfaces that for which protection is either not need or is not desired. In addition, the smaller and/or thinner the glass article, the more difficult it is to protect some of the glass' surfaces, particularly edge surfaces. Further, since many glass articles are cut from large sheets of glass, edge protection is of high importance, particularly for small to medium electronic devices such as cell phones, e-book readers, electronic notepads, notebook and laptop computers, and similar devices.
Several techniques have been tried to strengthen the edge of the glass. One approach has been to acid etch the glass edges to gain strength. Other methods have been described in US Patent Application Publications 2010-0282260, 2010-285277 and 2010-0221501 which include protecting the glass edge using polymer overmolding, a machinable metal armor layer laid over the edge, polymer tapes and liquid polymers, or a shaped fiber such as a glass fiber. However, each has proven unsatisfactory for varying reasons such as they were labor intensive, were not susceptible to automation, required additional processing steps which increased costs, or the edge protection material had to be molded over the edge onto the face of the article which can be undesirable from aesthetic and tactile viewpoints.
Despite all the efforts put forth, there still exists a need for a method of coating multiple glass edges, including profiled edges, for example edges around a glass article that are flat, bull nosed, chamfered or have other shapes. The flexibility of being able to coat edges having different shapes is extremely important and desirable, particularly when it comes to various device shapes and sizes, and in some cases there is no bezel frame around the display (that is, a only glass-to-glass display). Further, it is desirable that the method of applying the protective coating not only provides for uniformity and damage resistance, but the coating itself should be either optically clear or substantially transmissive to light wavelengths in one or more of the infrared (“IR”), visible, and ultraviolet (“UV”) wavelength ranges. Further, it is desirable is some application that the coating to be non-apparent; that is, the glass should appear to the user of the articles as if it is not coated at all.
The present disclosure is directed to a method of coating edges, particularly shaped edges; a device that can apply a coating to the edges and additionally has an interchangeable element so that it can be used to apply a coating to edges having different shapes; and to particular coating that can be used to coat the edges to provide a protected edge in which the coating